(1) material
1.5cm wide 150 cm long white tape (white tape), waste 135 film.
(2) Apparatus
Steel tape measure, cloth tape measure, ink pen.
Second, the method steps
(A) the criteria for determining the difference in chest circumference
See Biology (Volume II), a textbook for junior high schools of nine-year compulsory education, for the criteria for judging the difference in chest circumference.
(2) For the measurement method of chest circumference difference, please refer to pages 66-67 of junior high school biology of nine-year compulsory education (Volume II).
(3) Making simple tape measure
If you can't find a steel tape measure or cloth tape measure, students can make their own cloth tape measure or film tape measure, and the making method is relatively simple.
1. Tape Method A white inch tape with a width of 1.5 cm and a length of 150 cm was laid flat on the desktop and measured with a meter ruler. Draw a horizontal line (with ink pen) every 1cm, and indicate 1, 2,3 3… 10/0 or 100 cm to 150 cm. If conditions permit, white inch can take starch slurry once and dry it before marking it. You can also apply glue to the tape measure after marking to make the tape tough, so as to avoid affecting the accuracy due to different stretching tightness during measurement.
2. Film tape method allows students to find some used 135 films (negatives) or waste films. It is also an ideal, economical and applicable marking coating surface.
(4) Problems that should be paid attention to
1. If this experiment is conducted in the same class for boys and girls, it is better to find two rooms for boys and girls to measure separately, which makes it easier to organize teaching.
2. When measuring the difference of chest circumference, the subjects should take off their underwear, and girls only wear vests. Therefore, we should pay attention to keeping warm indoors to prevent catching a cold.
3. Students with skin diseases should not use cloth belt to measure. When they measure, they should use a steel tape measure. After use, they must wipe the disinfection tape measure with a cotton ball containing 70% ~ 75% alcohol by volume to prevent mutual infection.
(5) The key to success
1. This experiment is easy to carry out, and the key lies in organizing teaching, measuring in strict accordance with the experimental requirements, and measuring data should be accurate.
2. If the whole class measures, students can be mobilized to bring their own steel tape or cloth tape, or they can be mobilized to make their own simple cloth tape or film tape, of which the film tape is the most economical and can be replaced.
Third, teaching suggestions
(A) Teaching organization
1. This experiment can be carried out in the experimental class or in extracurricular activities. Before the measurement, the teacher should explain clearly to the students the standards, methods and precautions of chest circumference difference measurement, so that the students can measure each other.
2. Fill in the measurement results in the form designed by yourself. Summarize by the teacher and find out the relationship between age, sex, vital capacity and chest circumference difference.
(2) Experimental work
1. Please briefly describe the standards and methods for measuring chest circumference difference.
2. What is the relationship between chest circumference difference and vital capacity and chest circumference difference?